Track Tech Q&A - NASCAR Reads Circle Track!

It was several years ago that CT began Project G.R.E.E.N. (which stands for, Green Racing Experimental Engine Narrative), whereby a team of experts dyno tested, track tested, and raced a modern General Motors electronically fuel injected, E85-burning Late Model race car engine. We were then pushing the envelope as to what CT should be involved in politically, but thought we should proceed based on the value of the project. We were not disappointed at the outcome.

We knew through certain sources that persons higher up in the stock car racing community were taking note of our proceedings and that kind of put the pressure on. Just recently, lo and behold, on November 15, 2012, (some two and a half years after we first cranked Project G.R.E.E.N.'s engine), NASCAR began testing a similar configuration at Daytona for Sprint Cup cars. Editor Rob Fisher and I were there to witness this monumental event.

Now we are well aware that ASA, under different leadership and ownership than at present, had run a national racing series that used LS1 engines for several years and that program was a huge success. But what happened to that concept? Maybe it was ahead of its time then, but evidently not now.

It seems that racers will say they don't give a hang about what is happening in Cup, but when they fine tune their aerodynamics or run large sway bars and soft springs, it proves that the short track guys emulate what is going on in NASCAR, for better or for worse.

What we are hoping for is this; now that NASCAR has embraced the FI induction, ASA can be the first short track sanction to return to running FI engines. This will entice other sanctions to follow suit and we can be off on a more current track when it comes to our race engines.

We all know, or suspect, that the age of carburetors is coming to an end. Think about how long FI has been around in production cars. And our youth is growing up with FI cars, not normally aspirated carbureted engines.

The future of circle track racing depends on attracting our youth and making racing interesting. Imagine a world where the rules will allow a race team to tune their own engines on a computer. Kids are now well versed in computer technology and playing games much more complicated than a silly engine tuning program.

Modern FI engine management systems allow adjusting fuel feed and ignition timing for each cylinder individually and independent of the other cylinders. With optimum air to fuel ratios being maintained by the system itself, the driver has more torque and HP at all parts of the rpm range. The motors will last longer, the performance will be better, the fuel mileage will increase all of which will save the team money, and this will create more interest in racing in general.

We can also now utilize alcohol-based fuels such as E85 so that certain emissions will be reduced if we incorporate the FI engines. We've already shown the positive results of running these fuels in past articles related to the G.R.E.E.N. racing project.

Will there be opposition to this plan? Probably so, but as with any major change in the way things are done, you'll always have those who don't want to see change and want to maintain the status quo. But we can't afford to let technology pass us by. Now is the time to move ahead and create race cars that more resemble street cars and one of the most important components that needs to match up is the engine.

Many companies are now gearing up to accommodate the switch to FI engines. Those who aren't will soon be making preparation. The industry can and will adjust and our race cars will be better and more earth friendly as a result. It's a win/win situation.

If you have comments or questions about this or anything racing related, send them to my email address: Bob.Bolles@sorc.com, or mail can be sent to Circle Track, Senior Tech Editor, 9036 Brittany Way, Tampa, FL 33619.

Used Chassis Information

I'm a new subscriber to Circle Track and was wandering if you ever had or are going to ever do a story on used chassis? I want to get into racing dirt and need info on how old of a chassis is still good so I would be competitive.

I hear and see all the ads for chassis for sale that have been updated, and of course I'd like to be up to date. Just an example would be a '99 Shaw Modified vs. a 2005 Shaw Modified or an '01 Rocket Late Model vs. '07 Rocket Late Model.

These are just examples but without calling every chassis maker, someone like me just doesn't know. Maybe you have broken this down and maybe you haven't, but the info would be very, very helpful for starters like me.

Some of the info I'm interested in are the updates chassis makers perform, such as the '05 Shaw Mod relocated rear arms to accommodate something that is needed to be more competitive.

An article about so and so won with a 7-, 10-, or 14-year-old chassis would be great reading. Anyway, thanks for reading this and if possible send email back of year and date of the issue that has the info needed and I'll keep my eyes open for new articles in Circle Track. Thanks and keep the info coming.

- Doug

Doug,

It would not be cost effective for anyone to try to keep track of all the changes chassis builders make to their cars. Some builders keep their cars basically the same year after year and some make changes weekly it seems.

I have to believe that every chassis builder makes changes based on the belief that the car will be better as a result. It only makes sense. And I know for a fact that many car builders have embraced the concept of moment/roll center design and have updated their cars front ends as a result.

Another thing to remember is that racers are constantly searching for new setups and making changes to their shock package and spring package. So, the chassis builder must accommodate those trends with a chassis that will work best for what the racer is doing setup wise.

As far as running an older dirt chassis, I can tell you that dirt tracks are rough on racing chassis and after a few years, the metal is fatigued, bent, broken, and worn out. The cost of a newly constructed Late Model or Modified chassis is not prohibitive. If I were starting out, I would buy a good used chassis at a good price with lots of good parts on it, then replace the chassis and bolt on all of those cheaply acquired parts and go racing.

Moment Centers For NE Dirt Modifieds

I finished reading your article on moment centers in the Dec. '11 issue. I find your articles interesting. I have a question comparing your recommendations for moment centers on dirt cars and what are run on northeast DIRT Modifieds. These cars run straight front axles, the Panhard bars are mounted in the center of the axle, sometimes 1 or 2 inches below. The front coilovers look like they are mounted slightly to the left on the axle.

2/2

From what I understand about the moment center on a straight axle this would put the moment center at about 9 inches high and just left of center. This seems high for a car with an engine set back so far (the rear machined surface of the engine block is 56 to 66 inches back from the center of the axle) with 64 to 66 percent rear weight and 52 to 54 percent left-side weight.

I know they usually run a stiffer LF spring by about 100 pounds. Could you please explain or do an article explaining how they get the front ends of these cars to work so well or maybe an article on the geometry of straight axle front suspensions? I know they are antiquated but they are out there. Thanks for all your great information.

- Fred Ehlert

Fred,

When I speak of front moment center location, I'm always talking about a double A-arm front suspension. For a straight axle front end, the moment center height is the average height of the centers of the ends of the Panhard bar.

As for lateral location, the car ôfeelsö the MC midway between the top of the spring mounts. It doesn't matter where the Panhard bar is mounted, this lateral MC location is related to the spring locations on a straight axle suspension be it front or rear.

Teams like Brett Hearn and others make the front end work by balancing the setup in the cars. If you noticed, Brett drives in straight, through the middle straight, and off the corners mostly straight. The left front wheel is almost always in contact with the racing surface and carrying load. It's not really magic, just knowing how to arrange your spring rates to accomplish a dynamic balance. We have run numerous articles on that process. Go to www.circletrack.com to find past articles that will help you with your setup.

Trouble Cornering, Bite Off

I have a Chevy Monte Carlo with a 9-inch Ford Moser rearend (pinion 6 degrees) Late Model asphalt oval track car. I'm having an issue with cornering and no bite off the corner. I figure it's a roll center issue since we've tried everything else that we can think of. We recently switched to the Ford rearend and have had the issue since the installation.

I need to know what type of angle the upper control arms on the rearend should be because of the height of the Ford 9-inch or any other info you might be able to give us.

Cheers,

- Charlie Wilkins

Charlie,

It's a bit difficult to understand your issue without more information. But, from what you've provided, you might have a problem created when switching to the Ford rearend and it could be related to the rear moment center height.

If this is a car with the metric four-link type of rear suspension, and from your description you refer to upper control arms, plural as if there were two, then we might be on to something. If the rearend mounts were higher on the Ford differential than the Chevy, then that would raise the rear moment center and cause the car to be looser than it were before.

So, if for instance, the car were neutral before the swap, it would now be loose with the new higher rear MC. The solution is to try to lower the rear end mounts to the height of the Chevy mounts, or you might need to soften the right rear spring rate and/or stiffen the left rear spring rate to compensate for the higher and stiffer rear MC.